Towns of ancient Greece in the context of "Fortifications"

A fortification (also called a fort, fortress, fastness, or stronghold) is a military construction designed for the defense of territories in warfare, and is used to establish rule in a region during peacetime. The term is derived from Latin fortis ("strong") and facere ("to make").

From very early history to modern times, defensive walls have often been necessary for cities to survive in an ever-changing world of invasion and conquest. Some settlements in the Indus Valley Civilization were the first small cities to be fortified. In ancient Greece, large cyclopean stone walls fitted without mortar had been built in Mycenaean Greece, such as the ancient site of Mycenae. A Greek phrourion was a fortified collection of buildings used as a military garrison, and is the equivalent of the Roman castellum or fortress. These constructions mainly served the purpose of a watch tower, to guard certain roads, passes, and borders. Though smaller than a real fortress, they acted as a border guard rather than a real strongpoint to watch and maintain the border.

Alexandria on the Indus (Greek: Ἀλεξάνδρεια ἐπὶ Ἰνδῷ, likely modern Uch, Pakistan) was a city founded by Alexander the Great at the junction of the Indus and the Acesines river. Arrian tells that colonists, mainly Thracian veterans and natives, were settled there.

The satrap of the west bank of the Indus, Philip, son of Machatas, was put in charge of building the city: